Multiple antennas can be used to i) increase the antenna gain by beamforming; ii) provide diversity gain through some form of antenna combining; iii) increase the data rate by spatial multiplexing; and iv) suppress spatial interference by null steering. However, a system with multiple antennas may be unable to take advantage of all of these benefits if the system cannot accurately estimate and track a wireless communications channel.
Further limitations and disadvantages of conventional and traditional approaches will become apparent to one of skill in the art, through comparison of such systems with some aspects of the present invention as set forth in the remainder of the present application with reference to the drawings.